Use a simple for-loop instead of MappedIterator
Use a string for indentation
Remove BinaryOpParser
Make getValues and getDescriptions free functions
Show help message for positional options
Add a virtual destructor for OptionBase
Check for option groups only if the option is specified with a single hyphen
Save the length of the longest prefix option
Add MayPrefix flag. Always include the equals sign in the value for prefix options.
Store unknown command line arguments
Add a function to construct options using a MapParser
Fix VC warnings
Pass the specified option name to the parser.
Add the possibility to specify multiple names for an option
Update the test app